Order wire accommodation system for interoffice communications

Abstract

An order wire accommodation system comprises four interface boxes each of which has the same order wire interface section as the others. The order wire interface section has a circuit which digitally adds order wire signals of the transmission lines from two ports and the order wire signals which interface with the other interface boxes or a telephone through the other two ports. Each output from the order wire interface section is a sum of all the order wire signals inputted except for those of the order wire interface section itself. Because of a provision of two ports which interface externally, the interface boxes can be cascaded connected to one another, by which order wire communications among all the transmission lines accommodated in the interface boxes become possible. Further, the order wire accommodation system can be minimized and be simplified.

What is claimed is: 
     
       1. A minimized and simplified order wire accommodation system including at least two interface boxes, each interface box comprising: two transmission line interface sections for interfacing with transmission lines; and   a single order wire interface section having interfaces including two first ports for order wire signals from the transmission lines and two second ports for order wire signals to be interfacing with an external order wire line,   the two first ports being connected to the transmission lines which are connected to a communication device of another office,   the two second ports being cascade connected to the second ports of the neighboring interface boxes through the order wire lines, and   one of the two second ports of one order wire interface section serving as a connection end of a cascade connection among a plurality of interface boxes being connected to a telephone through a telephone interface line.   
     
     
       2. An order wire accommodation system according to claim 1, wherein: the order wire interface section adds the order wire signals of the two first ports and the order wire signals of either one of the two second ports.   
     
     
       3. An order wire accommodation system according to claim 2, wherein: the added order wire signals of the two first ports and one of the two second ports are outputted from the other one of the two second ports.   
     
     
       4. An order wire accommodation system according to claim 3, wherein: one of the two second ports of each one of two or more interface boxs is connected to the closer one of the two second ports of a neighboring interface box, thus forming a cascade connection among the interface boxes.